Conventionally, in grinding a panel face of a cathode ray tube, a tubular, woven felt which is attached to a rubber drum mounted on a pressurized air grinding machine is used. Such a woven felt conventionally comprises a fabric woven from a yarn made by mix spinning wool and nylon and subsequent milling of the yarn in an acidic or alkali solution.
In using the above-mentioned conventional tubular felt for grinding, the quality of the obtained ground panel face is fairly good. However, since its glass grinding capability is somewhat inferior, the time required for the grinding operation is prolonged and since its anti-wear property is also insufficient, its useful life is rather limited.
On the other hand, when using a tubular felt made of synthetic fibers, since its porosity is relatively small, water may not be retained in the felt. Moreover, the hygroscopic property of the fiber itself is inferior and heat generated during the grinding operation may not be readily radiated. Thus, due to the heat generated during the grinding operation, the fibers tend to melt and form a membrane. When this phenomenon takes place, the ground particles tend to accumulate on the surface of the membrane, which in turn causes damage to the ground surface. Furthermore, although the synthetic fiber tubular felt is superior to the woven felt in terms of the grinding speed and durability, the quality of the finished surface is inferior with possible damage to the ground surface as mentioned above.